Jan. 5, 2000 (Cleveland) -- Men who really want a break today should pass up the Big Mac and dig into broccoli, cauliflower, kale, and cabbage, says a team of researchers from the Fred Hutchinson Cancer Research Center and the University of Seattle. When they compared the diets of men with prostate cancer with diets of healthy men, the Seattle team found that eating three or more servings of vegetables daily cuts the risk of prostate cancer by 48% compared with men who aren't digging into the veggies.
All vegetables are good for you, says Alan R. Kristal, PhD, but it turns out the cruciferous vegetables -- broccoli, cauliflower, brussels sprouts, cabbage, kale -- do the most good. Kristal is a co-author of the study, which is reported in the January issue of the Journal of the National Cancer Institute.
Kristal tells WebMD that fruits offered no protective effect. "This isn't surprising since, in my opinion, the only nutrient in fruit that might play a role is vitamin C, and I don't think that anyone is suggesting that vitamin C is protective against prostate cancer," Kristal says.
Kristal and his colleagues studied the diets of 628 men from the metropolitan Seattle area who were newly diagnosed with prostate cancer. The data collected from those men were compared to similar dietary information collected from 602 age-matched healthy males.
"We studied young men between the age of 40 and 64," says Kristal. By studying younger men, "especially those under 60, it allows us to tease out the environmental effects that cause prostate cancer as opposed to the inevitable march of time that is the major cause of prostate cancer." While prostate cancer is relatively rare in young men, it is the most common cancer among men aged 65 or older, he says.
Kristal says that most men consume about "1.5 servings of vegetables a day, so they would have to double the intake of vegetables to experience this protective effect." For men who think that means more fries and baked potatoes, think again. Kristal says that "French fries don't count as a vegetable, and generally we did not find a protective effect for potatoes."
Although recent reports have suggested that tomato products, especially sauces that are rich in the tomato extract lycopene, protect against prostate cancer, Kristal says his team found no special protection offered by tomatoes. He says that tomatoes may, however, be protective as part of total vegetable consumption.
Kristal says that a change to a diet heavy on the vegetables and light on the fats is especially important for "a man in his 40s who has a family history of prostate cancer." A diet high in fat actually increases the risk of prostate cancer. Thus, some of the protective effect of increasing dietary vegetables may be that the vegetables "serve to displace fat in the diet. Or it may be that once a person commits to eating more vegetables, he or she decides to adopt a total healthier diet."
In an interview about the effects of diet and vitamins on cancer risk, Jeffrey Blumberg, PhD, professor of nutrition and chief of the antioxidants lab at Tufts University School of Nutrition and Health, tells WebMD, "It is naive to think that we will find a nutritional magic bullet to fight cancer. The carcinogenic process is enormously complex, and there is not a single nutritional pathway that will provide an answer." He says, however, that a study such as the work by Kristal and colleagues "is very exciting" and adds to the mounting evidence that nutrition is an important part of the cancer puzzle.
Kristal says that opting for a healthier diet is not difficult and can be as simple as "deciding not to go to McDonald's and going instead to a Chinese restaurant."
- Eating three or more servings of vegetables each day can cut the risk of prostate cancer by 48%, and cruciferous vegetables provide the most benefit.
- Research showed that fruits offer no protection, and a diet high in fat increases the risk of prostate cancer.
- Researchers suggest that increasing vegetable consumption may serve to replace dietary fat or may be associated with people who have overall healthier lifestyles.